WASHINGTON, D.C. -- A federal judge wants an investigation into the State Department for delays in prosecuting security guards with Blackwater -- the agency founded by Holland native Erik Prince -- over Iraqi civilian killings.

The case against four guards with the security company once called Blackwater, then renamed, has been stymied for years.

The delays were largely because of grants of legal immunity for sworn statements from the guards.

In an opinion by U.S. District Court Judge Royce Lamberth, the judge accused the State Department of causing the delays. He also denied a motion to dismiss the indictments against the guards, who are set for trial in June.

In the opinion, the judge wrote: "The injustice done to the alleged victims of this incident by the last seven years of litigation has been totally unwarranted."

He called it "disturbing" that it took seven years to prosecute the case.

"If the Department of State and the Diplomatic Security Service had tried deliberately to sabotage this prosecution, they could hardly have done a better job. It is incredible the way these defendants were coerced into making statements to DSS agents.

"The impropriety of this was well-settled law at the time," he wrote. "Even more egregious, though, was the leaking to the news media of all the statements given. Yet it appears there has been no investigation of these circumstances and no one has been held accountable.

"Nor is there any reason to think anyone learned a lesson from this fiasco or that any steps have been taken to avoid a repetition."